Incandescent lamp



l Sept. 21,` 1937. G. PIERslMoNl Er ALA 2,093,523

4INC!^.NDESCEN'I LAMP Filed March 20. 1935 FIG. 2

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` insulating material, such as bakelite or other phenol-formaldehyde condensation products, or urea-formaldehyde, or other similar material, is secured by a non-conductive cement, or another similar agent, upon the bulb I around its lower end. Centrally upon the bottom of the base 29 there is arranged a contact 30, from which a wire 3l extends and branches out into the two parallel wires 32 and 33.

Two return wires 34 and 35 are arranged parallel on the outer sides of wires 32 and 33, respectively; the outer end of the wire 35 is drawn out between the bulb` Ill and the rim of the base 29 and is connected at 36 with a metal strip 3l which is retained by a flattened bayonet pin 38 within one of the grooves 39, cut longitudinally into the base 29 on opposite sides thereof.

In another groove 39 there is arranged a metal strip 4f! provided with a slot 4|, through which a flattened bayonet pin 38 passes so as to hold the metal strip or switch 40 tightly, but slidably in the groove 39.

At the end of the groove 39 which accommodates the switch 43, is arranged a contact 42, to which the outward end of the wire 34, passing through between the bulb I9 and the rim of base 29, is connected. In order to make a good connection with this contact 42, the switch 4l! is provided at its adjoining end with a slight dent which will come to press upon contact 42 when the switch 49 is shifted upwardly.

For purposes of reinforcement and alignment the wires 34, 32, 33 and 35 are embedded in a glass bead 43. A filament 44 connects the inner ends of wires 34 and 32 and a filament 45 connects those of the wires 33 and 35.

When this improved bulb is tted into a lamp socket with the pins 38 engaged in slots formed in the walls thereof in the usual manner, the

switch 4l! is off contact 42 and therefore the iilament 45 will be energized; should this filament burn out, the bulb is taken out and the switch 40 shifted upon contact 42, and upon re-insertion of the bulb into the lamp socket, the filament 44 will be energized.

Instead of a groove of a rectangular crosssection, as has been shown in groove 39, I may construct the groove so as to have a dove-tail cross-section as illustrated by Figure 3. There the base is provided with a channel 41 of dovetail cross-section, which slidably accommodates sheet metal or switch 48. From an inspection of Figure 3 it will be noticed that the switch 48, suitably of brass, has its edges bent up so as to form a slide of dove-tail cross-section, which will t into channel 41; as it sides display some spring action and touch the adjoining walls, the friction between these parts holds, or contributes to hold, the switch 48 in place. Projections 49 facilitate the shifting of switch 48 in the well known way.

In Figure 4 there has been shown a further modified form of switch construction in connection with the contact 42 shown in Figure 2, from which it is obvious that a strip of metal, or switch 59, is hingedly connected with the pin 38 and normally rests within the groove I which is sunk into the peripheral face of the base 29 substantially parallel to its upper rim. The switch 50 is of arcuate form So as to conform to the peripheral surface of base 29 and has a scooplike terminal with a lateral projection to facilitate its manipulation. Another groove 52 receives the contact 42 and communicates with the groove 5I so that the switch 50 may be turned to engage contact 42.

On account of the arcuate form of the switch 5U, the same also displays some spring action when turned into the groove 52 and its scoopshaped terminal is therefore tightly pressed upon contact 42.

It is, of course, understood that the construction of our new incandescent lamps is not restricted to arrangements with two filaments only, but that with the increase in the size of the lamps we may increase the number of lateral contacts I1, which would all be arranged in an annular path, so that the lug of the rotarily arranged spring 26 may consecutively connect to each of the contacts I1. As diagrammatically shown in Figure 6 there may be many of these contacts Il as long as the spring may be conveniently positioned between two such contacts l1 without contacting with the same if not desired.

We are also not restricted in the number of independent Wires, such as 33 and 34, as is selfevident from Figure 5, where we show that, dependent'on the length of the circumference of the base 29, we can provide a number of grooves 39 to receive contacts 42 connected with the independent wires.

In both cases the laments connecting the ends of the wires with the ends of the branch wires are very much more apart from each other so that at the burning out of one wire none of the others are affected.

What we claim is:

1. In an incandescent multiple filament lamp the combination of a bulb, a base of insulative material secured to the bulb at its end, a plurality of grooves arranged longitudinally of the base, a bayonet pin arranged within each of said grooves, a contact arranged upon said base, a wire extending from said contact and branching into a plurality of wires, a metal strip rigidly held in one of aforesaid grooves by a bayonet pin, a metal strip held slidably arranged by a bayonet pin in each of the other of aforesaid grooves, a contact within each of said grooves, a plurality of independent wires extending along aforesaid branch wires, one of said independent wires connecting with the aforesaid rigidly held metal strip and one each of the others with the contact in the other grooves, and filaments connecting pairs of the ends of the independent and of the branch wires.

2. In an incandescent lamp provided with filaments, a bayonet base and terminals on said base by way of which current is admitted to said lamp, a movable contact member on the cylindrical surface of said base electrically connected with one of said terminals, and slidable upon said surface between contact make and break positions, and a second contact member in make and break alignment with said first member and electrically connected with one of said filaments.

3. In an incandescent lamp provided with multiple filaments and a bayonet pin base, a switch forming part of said base, movably retained by one of the bayonet pins of said base and comprised inthe circuit of one of said filaments within said lamp.

GIOVANNI PIERSIMONI. HENRY S. FRIEDMAN. 

